Why do we Yawn
Yawn not unique to man. They say that even a frog yawn. Yawning is a reflection of the ancient instinct that has existed in all animals. People are able to empathize, to see people yawning, too, begin to yawn. Yawning - employment is extremely contagious. Yawn for the company in 42-50% of cases, but this action can not be children under four years. Chimpanzees, like humans, are able to yawn for the company.
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